String holder



FIG. 1 is a perspective front view of string holder, showing my new design;

FIG. 2 is a front side view thereof;

FIG. 3 is a back side view thereof;

FIG. 4 is a left side view with the right side view being a mirror image thereof;

FIG. 5 is a top side view thereof; and,

FIG. 6 is a bottom side view thereof.

The dashed lines form a boundary area and form no part of the claimed design. 

CLAIM The ornamental design for a string holder, as shown and described. 